Question

Determine the factors of 5x2 + 6x − 8.

Answer 1

C

Explanation:

use ac method

for ax^2+bx+c

multiply a and c

find what 2 numbers multiply to get ac and add to get b

split b into those 2 numbers

group

factor

factor

5x^2+6x-8

ac=5 times -8=-40

what 2 numbers multiply to get -40 and add to get 6?

-4 and 10

5x^2+10x-4x-8

group

(5x^2+10x)+(-4x-8)

factor

5x(x+2)-4(x+2)

factor

(5x-4)(x+2)

C is the answer

Answer 2

`\large\boxed{5x^2+6x-8=(x+2)(5x-4)}`

Explanation:

`5x^2+6x-8\\\\=5x^2+10x-4x+8\\\\=5x(x+2)-4(x+2)\\\\=(x+2)(5x-4)`